Guy Derrick

A derrick consisting of a single spar or mast set on end and secured by guy wires at the upper end, having fastened to its lower end a boom or jib carrying a hoisting tackle at top of boom for raising and lowering heavy weights. The boom is so arranged that it may be raised or lowered at different angles or swung horizontally. The hoisting unit is generally not an integral part of this device but may be mounted any distance from the derrick.